Problem: Solve for $x$. $3x^2 + 18x + 27 = 0$ $x = $
Explanation: Dividing both sides by $3$ gives: $ x^2 + {6}x + {9} = 0 $ The coefficient on the $x$ term is $6$ and the constant term is $9$, so we need to find two numbers that add up to $6$ and multiply to $9$. The number $3$ used twice satisfies both conditions: $ {3} + {3} = {6} $ $ {3} \times {3} = {9} $ So $(x + {3})^2 = 0$. $x + 3 = 0$ Thus, $x = -3$ is the solution.